Implantable neurostimulation systems have proven therapeutic in a wide variety of diseases and disorders. Pacemakers and Implantable Cardiac Defibrillators (ICDs) have proven highly effective in the treatment of a number of cardiac conditions (e.g., arrhythmias). Spinal Cord Stimulation (SCS) systems have long been accepted as a therapeutic modality for the treatment of chronic pain syndromes, and the application of tissue stimulation has begun to expand to additional applications such as angina pectoralis and incontinence. Deep Brain Stimulation (DBS) has also been applied therapeutically for well over a decade for the treatment of refractory chronic pain syndromes, and DBS has also recently been applied in additional areas such as movement disorders and epilepsy. Further, Functional Electrical Stimulation (FES) systems such as the Freehand system by NeuroControl (Cleveland, Ohio) have been applied to restore some functionality to paralyzed extremities in spinal cord injury patients. Furthermore, in recent investigations Peripheral Nerve Stimulation (PNS) systems have demonstrated efficacy in the treatment of chronic pain syndromes and incontinence, and a number of additional applications are currently under investigation. Occipital Nerve Stimulation (ONS), in which leads are implanted in the tissue over the occipital nerves, has shown promise as a treatment for various headaches, including migraine headaches, cluster headaches, and cervicogenic headaches.
These implantable neurostimulation systems typically include one or more electrode carrying neurostimulation leads, which are implanted at the desired stimulation site, and a neurostimulator (e.g., an implantable pulse generator (IPG)) implanted remotely from the stimulation site, but coupled either directly to the neurostimulation lead(s) or indirectly to the neurostimulation lead(s) via a lead extension. Thus, electrical pulses can be delivered from the neurostimulator to the neurostimulation leads to stimulate the tissue and provide the desired efficacious therapy to the patient.
The neurostimulation system may further comprise an external control device to remotely instruct the neurostimulator to generate electrical stimulation pulses in accordance with selected stimulation parameters. For example, the neurostimulation system may further comprise a handheld patient programmer in the form of a remote control (RC) to remotely instruct the neurostimulator to generate electrical stimulation pulses in accordance with the selected stimulation parameters. The RC may, itself, be programmed by a clinician, for example, by using a computerized programming system in the form of a clinician's programmer (CP), which typically includes a general purpose computer, such as a laptop, with a programming software package installed thereon.
Electrical stimulation energy may be delivered from the neurostimulator to the electrodes in the form of an electrical pulsed waveform. Thus, stimulation energy may be controllably delivered to the electrodes to stimulate neural tissue. The combination of electrodes used to deliver electrical pulses to the targeted tissue constitutes an electrode combination, with the electrodes capable of being selectively programmed to act as anodes (positive), cathodes (negative), or left off (zero). In other words, an electrode combination represents the polarity being positive, negative, or zero. Other parameters that may be controlled or varied include the amplitude, width (or duration), and frequency (or rate) of the electrical pulses provided through the electrode array. Each electrode combination, along with the electrical pulse parameters, can be referred to as a “stimulation parameter set.”
With some neurostimulation systems, and in particular, those with independently controlled current or voltage sources, the distribution of the current to the electrodes (including the case of the neurostimulator, which may act as an electrode) may be varied such that the current is supplied via numerous different electrode configurations. In different configurations, the electrodes may provide current or voltage in different relative percentages of positive and negative current or voltage to create different electrical current distributions (i.e., fractionalized electrode combinations).
As briefly discussed above, an external control device can be used to instruct the neurostimulator to generate electrical stimulation pulses in accordance with the selected stimulation parameters. Typically, the stimulation parameters programmed into the neurostimulator can be adjusted by manipulating controls on the external control device to modify the electrical stimulation provided by the neurostimulator system to the patient. Thus, in accordance with the stimulation parameters programmed by the external control device, electrical pulses can be delivered from the neurostimulator to the stimulation electrode(s) to stimulate or activate a volume of tissue in accordance with a set of stimulation parameters and provide the desired efficacious therapy to the patient. The best stimulus parameter set will typically be one that delivers stimulation energy to the volume of tissue that must be stimulated in order to provide the therapeutic benefit, while minimizing the volume of non-target tissue that is stimulated.
However, the number of electrodes available, combined with the ability to generate a variety of complex stimulation pulses, presents a huge selection of stimulation parameter sets to the clinician or patient. For example, if the neurostimulation system to be programmed has an array of sixteen electrodes, millions of stimulation parameter sets may be available for programming into the neurostimulation system. Today, neurostimulation system may have up to thirty-two electrodes, thereby exponentially increasing the number of stimulation parameters sets available for programming.
To facilitate such selection, the clinician generally programs the neurostimulator through a computerized programming system, such as the afore-described CP. This programming system can be a self-contained hardware/software system, or can be defined predominantly by software running on a standard personal computer (PC). The PC or custom hardware may actively control the characteristics of the electrical stimulation generated by the neurostimulator to allow the optimum stimulation parameters to be determined based on patient feedback or other means and to subsequently program the neurostimulator with the optimum stimulation parameter set or sets. The computerized programming system may be operated by a clinician attending the patient in several scenarios.
In order to achieve an effective result, the lead or leads must be placed in a location, such that the electrical stimulation will effectively treat the indentified disease or condition. If a lead is not correctly positioned, it is possible that the patient will receive little or no benefit from the implanted neurostimulator. Thus, correct lead placement can mean the difference between effective and ineffective pain therapy. When electrical leads are implanted within the patient, the computerized programming system, in the context of an operating room (OR) mapping procedure, may be used to instruct the neurostimulator to apply electrical stimulation to test placement of the leads and/or electrodes, thereby assuring that the leads and/or electrodes are implanted in effective locations within the patient.
Once the leads are correctly positioned, a fitting procedure, which may be referred to as a navigation session, may be performed using the computerized programming system to program the external control device, and if applicable the neurostimulator, with a set of stimulation parameters that best addresses the disease or condition. Thus, the navigation session may be used to pinpoint the stimulation region or areas correlating to the disease or condition. Such programming ability is particularly advantageous for targeting the tissue during implantation, or after implantation should the leads gradually or unexpectedly move that would otherwise relocate the stimulation energy away from the target site. By reprogramming the neurostimulator (typically by independently varying the stimulation energy on the electrodes), the stimulation region can often be moved back to the effective pain site without having to re-operate on the patient in order to reposition the lead and its electrode array.
It can be appreciated from this that the configuration of the leads (i.e., absolute and relative locations and orientation of the leads) is an important piece of information when programming a neurostimulator. This lead configuration information is typically readily available during implantation of the leads and is stored within the computerized programming system used during lead implantation in the OR. However, once implanted, subsequent programming of the neurostimulator requires this lead configuration information. Because the lead configuration information is only stored in the computerized programming system used in the OR, this same computerized programming system must be used during the navigation session or follow-up reprogramming session or the lead configuration information must be transferred from the OR computerized programming system to the new computerized programming system. However, in a clinical setting, it is quite common that the same computerized programming system is not available to program the neurostimulator, and there is a high likelihood that the neurostimulator is programmed or reprogrammed using a different computerized programming system (either in the same hospital/clinic or in a different hospital/clinic).
Stimulation applications, and thus the capabilities required to implement such applications, typically vary based on the clinical indications. However, the hardware contained in neurostimulators typically is designed to provide electrical stimulation capabilities that far exceed the requirements for the disease or condition for which it is intended to be used and is capable of being used for multiple clinical indications for widely different disease states. This is because most clinical indications share the same concepts and differ only by the numerical range of the features optimal for the particular clinical indication to be treated. The software and/or firmware contained in neurostimulators are typically designed to enable different ranges of features, depending upon the clinical indications for which they are intended to treat. As a result, different software packages for any particular computer programming system are typically required to respectively program the different types of neurostimulators. As such, multiple software packages must be loaded into a computerized programming system to provide it with the capability to program different types of neurostimulators, and if a computerized programming system in the field does not have the capability to program a particular neurostimulator type, the software package corresponding to that neurostimulator type must be ordered from the supplier and subsequently loaded into the computerized programming system. Furthermore, for each new type of neurostimulator that has been designed and released into the field, new programming software for the computerized programming system must be designed, tested (verification and validation), and released into the field.
There, thus, remains a need for an improved neurostimulator system that allows an external control device to program a neurostimulator implanted within a patient without having prior knowledge of the type of the neurostimulator and the configuration of the neurostimulation leads implanted within the patient.